Extend type support in non-federated types

[SirensOfTitan]

One fairly nice feature in the GraphQL spec is the capacity to extend types. This is particularly worthwhile when working with Mutation, as you can co-locate particular mutations with the rest of their GraphQL definitions. I've noticed the extends field sprinkled around in tests for federated features here, but I was wondering if there is or any support is planned for this feature.

For example, I could have a stub file, mutation.py:

@strawberry.type
class Mutation:
  pass

... and in say, foo.py:

@strawberry.type
class Foo:
  id: str
  
@strawberry.type(extends=True)
class Query:
  @strawberry.field
  def foo(id: strawberry.ID) -> Foo:
    ...
    
@strawberry.type(extends=True, name="Mutation")
class FooMutation:
  @strawberry.field
  def updateFoo(...) -> FooPayload: 
    ...

[patrick91]

Hi @SirensOfTitan! Thanks for the suggestion! 😊

Would you need to import FooMutation in your schema? At the moment all types have to be explicitly declared on the schema, either by using them as types of fields or by passing them to the types argument on the schema.

I don't think we might allow Strawberry to automatically find types[1], as we support creating multiple schemas in a single project.

If we don't allow finding automatic types, then maybe allowing to use extend to extend types, might not be the best DX? What do you think?

[1] but this could be something done by a framework/helper built on top of Strawberry maybe :D